"Richard Blackwood" wrote in message ...
Once again the hot weather has reminded me of just how much I dislike it!
Last night I noticed the amount of heat given of by my ordinary bedside
lamp - IIRC something like 80% of the energy in light bulbs is heat not
light. It made me wonder whether different bulbs would produce less heat?

Argos do a pack of 3 15 Watt BC Energy Saving Fluorescent Bulbs for £6.99

http://www.argos.co.uk/webapp/wcs/st...y?storeId=1000
1&langId=-1&catalogId=2501&productId=104088

These seem to have an ordinary 'bayonet' type fixing. Would these emit less
heat as well as being more efficient?

Can anyone shed some light on the subject?


All a bulbs power input becomes heat: about 98% of it becomes heat
directly, the rest becomes light, which turns to heat less than a
microsecond later as its absorbed. The power input always equals the
heat output.

CFLs are the solution, but dont be caught out by the one issue: the
stated equivalent powers are unrealistic, as they are comparisons with
a different type of bulb than everyone expects. The real efficiency
improvement is about 3.5x - 4x, so to replace a 60w bulb you need a
15-17 watts.

If you trust the box's equivalency claims, its dimmer and doesnt look
right.


NT

CFLs are the solution, but dont be caught out by the one issue: the
stated equivalent powers are unrealistic, as they are comparisons with
a different type of bulb than everyone expects.

I'm not sure I quite buy that. I think the equivalency is about right, but
you must run the bulb for five minutes before you make the comparison.

Christian.

"Christian McArdle" wrote in message .net...
CFLs are the solution, but dont be caught out by the one issue: the
stated equivalent powers are unrealistic, as they are comparisons with
a different type of bulb than everyone expects.

I'm not sure I quite buy that. I think the equivalency is about right, but
you must run the bulb for five minutes before you make the comparison.

Christian.


theyre compared to soft light bulbs, which have lower light output
than standard GLS ones.

Unfortunately this dim practice is their downfall, as it has led to
the popular perception that their light is inferior.


Regards, NT

"N. Thornton" wrote in message
om...
"Richard Blackwood" wrote in message
...

All a bulbs power input becomes heat: about 98% of it becomes heat
directly, the rest becomes light, which turns to heat less than a
microsecond later as its absorbed. The power input always equals the
heat output.

CFLs are the solution, but dont be caught out by the one issue: the
stated equivalent powers are unrealistic, as they are comparisons with
a different type of bulb than everyone expects. The real efficiency
improvement is about 3.5x - 4x, so to replace a 60w bulb you need a
15-17 watts.

If you trust the box's equivalency claims, its dimmer and doesnt look
right.


I must agree that the equivalencies do seem rather on the optimistic side,
to put it kindly.

Rick

On 8 Sep 2004 07:44:22 -0700, N. Thornton wrote:

If you trust the box's equivalency claims, its dimmer and doesnt
look right.

Yep, been caught like that. I now look for the little box that gives
the techy information, like (but not always) voltage, fitting code,
life, lumens, colour temperature.

For example a 60W incandescant has "240V 700 Lumen 1000h" on the
bottom of the box. Morrisons (=A32.99 for 2) 11W CFLs have "711 Lumen 11=

Watt 12000h". I have yet to try these cheapies and I'm fully expecting
the colour to be crap...

You can get decent colour temperature CFLs now though, just replaced
6x40W E14 candles with GE Tech Extra Mini 9W CFLs, there is actually
more light in the room now. Not cheap, =A36.98 each springs to mind from=

B&Q, but as these lights are on for 18hrs a day the reduction in the
power bill will have paid for them in about 9 months...

--
Cheers
Dave. pam is missing e-mail